Contact lenses that ride directly over the corneal surface of the eye, floating on a micro-thin layer of tear fluid, are widely prescribed to correct refractive errors in vision. However, the traditional method of fitting contact lenses is a laborious process, often requiring weeks of trying various lens shapes. Each fitting usually requires at least fifteen minutes before the patient is comfortable with the lens in place. Then the optometrist applies fluorescein dye drops to the patient's eye to reveal the amount of clearance between the contact lens and the corneal surface. Fluorescein is a bright orange dye that fluoresces lime green in the presence of cobalt blue light. It is relatively harmless although an occasional person may have an allergic response. In the lens fitting process, the more clearance between the contact lens and the cornea, the more dye is permitted in the space, as indicated by a fuller green fluorescence of the dye. The fluorescein test is considered quite reliable but is not usable with the popular soft contact lenses because the material from which they are made, hydrogel, absorbs the fluorescein dye, staining the lens. It would be useful to provide a method of fitting contact lenses which avoids the need to test multiple contact lenses in the patient's eye.